A conventional agricultural combine generally includes a header mechanism that severs and collects crop material as the combine is driven through a field, and a feeder mechanism that feeds the crop material to a threshing mechanism in the combine. The threshing mechanism includes a rotor assembly. The crop material is threshed as it passes between a rotor and a cylindrical housing of the rotor assembly.
Typically, the rotor has a front portion, a rear portion and an outer surface that is proximate the cylindrical housing. Generally, a number of thresher elements are secured to the outer surface. As the rotor rotates, crop material enters the rotor assembly and the thresher elements facilitate the flow of the crop material towards the rear portion and separate the seeds from the remaining plant material.
The thresher elements typically include both short elements and elongated thresher elements which are arranged in particular patterns or arrays to form helical paths. The crop material flows along these helical paths. Typically, the thresher elements are arranged so that the crop material will strike one short thresher element and then proceed to impact an elongated thresher element. Further, in a conventional rotor assembly two elongated thresher elements may be secured so that they lie along a common line parallel to the longitudinal axis of the rotor.
Crop material sometimes has a tendency to form clumps against elongated thresher elements. In addition, in the configuration where two elongated thresher elements are arranged along the same line, a roll of crop material may form against the multiple elongated thresher elements. Such clumping and formation of rolls can affect the capacity of the rotor assembly. Further, when the rotor encounters clumps or rolls of material, increased horsepower may be required to maintain a normal threshing operation. This increased horsepower requirement can result in a torque spike in the rotor, which generally tends to decrease the effective life of the rotor and, possibly, of the rotor drive.